JP5962836B2 - Rapid hardening additive for cement and method for producing the same - Google Patents

Description

  The present invention relates to a rapid hardening additive for cement and a method for producing the same, and in particular, it is added to an arbitrary cement to give excellent rapid hardening to the cement not only at room temperature but also at a low temperature, and has a predetermined fluidity. It is related with the quick-hardening additive for cements and the manufacturing method which are excellent also in workability by having.

In recent years, in construction work for tunnels and underground spaces, a spray construction method has been widely practiced in which a cement mixture such as mortar and concrete is blown and lined on a wall surface or an exposed surface to prevent the wall surface or the exposed surface from collapsing.
In this concrete spraying method, concrete is prepared, and the minimum usable time (handling time) necessary for handling it is secured, and after spraying on the wall surface or exposed surface, the concrete is immediately cured. It is necessary to let
In addition, it is necessary to secure the pot life of mortar and concrete in water stoppage work and emergency work and to harden it immediately.

Conventionally, as a cement having rapid hardening, a rapid hardening cement such as jet cement has been manufactured. As the clinker used in these, there are a jet cement clinker, an Irwin clinker whose main component is C ₄ A ₃ SO ₃ , an alumina cement clinker whose main component is CA, and the like.
There is also a method of obtaining amorphous C ₁₂ A ₇ by melting a clinker mainly composed of C ₁₂ A ₇ which is a rapid hardening component and then rapidly cooling it.

In particular, the conventional jet cement clinker is a clinker containing a calcium silicate phase as a main component and containing about 20 to 30% by weight of C ₁₁ A ₇ · CaF ₂ as a fast-hardening component, such as C ₁₁ A ₇ CaF ₂ or C ₄ AF. A melt phase such as the above is generated. Accordingly, if the content of C ₁₂ A ₇ that is a rapid hardening component is set to be in the above range or more, the melt phase becomes excessive, the clinker is melted, and for example, it is very difficult to manufacture with actual equipment.

Irwin-based clinker is used as a clinker for quick-hardening cement because it contains 70% by weight or more of erwin (C ₄ A ₃ SO ₃ ) having quick-hardness. There is a problem that it is inferior in rapid hardening at low temperature.
Furthermore, the alumina cement clinker containing CA as a main component is inferior in rapid hardening as compared with the clinker containing C ₁₂ A ₇ as a main component.

As a quick-hardening clinker, Japanese Patent No. 4616113 (Patent Document 1) has a content of C ₁₂ A ₇ or C ₁₁ A ₇ · CaX ₂ (X represents halogen) before firing in a reducing atmosphere. The C ₁₂ A ₇ or C ₁₁ A ₇ · CaX ₂ (X represents halogen) was measured by X-ray diffraction by firing at 1300 to 1380 ° C. in a reducing atmosphere. A rapid-hardening clinker is disclosed, characterized in that the lattice constant is from 11.93 to 11.96.

Furthermore, Japanese Patent No. 3179702 (Patent Document 2) discloses a clinker composition used for quick setting cement, quick setting material, quick setting cement, ground improvement material, masking material, etc. · _7Al the 2 _{O 3} based clinker raw material whose main component is calcium aluminate, _Fe 2 _{O 3} the total 0.1 to 9% by weight of, be 0.1 to 9 wt% containing coexistence entire CaF ₂ To produce a low-temperature melt phase and a high-temperature melt phase, and by adding 0.5 to 9% by weight of TiO ₂ , the melting start temperature of the low-temperature melt phase and the high-temperature melt phase can be reduced. A quick-hardening clinker composition characterized by being reduced and fired is disclosed.

Since these conventional cement clinker promotes the solid phase reaction, it is necessary to actively generate a melt phase. If the melt phase is small, the solid phase reaction does not proceed and the clinker mineral production does not proceed well. On the other hand, since excessive production of the melt phase becomes a problem in clinker production, it is necessary to adjust the amount of the melt phase to be generated so as to fall within a certain range.
In particular, the clinker disclosed in Patent Document 2 has a C12A7 mineral content increased as compared with a jet clinker, and produces a C12A7 mineral phase by a solid phase reaction. At this time, Fe and Ti are added to generate an appropriate amount of melt phase to obtain a clinker.
Moreover, the C12A7 mineral of the conventional clinker is a solid solution, and the solid solution state of the C12A7 mineral is changed by the inclusion of Fe or Ti, which affects the hydration activity of the C12A7 mineral.

Such a conventional cement clinker does not obtain sufficient strength, for example, 3 hours, which is desired hardness not only at room temperature but also at low temperature, and it has been difficult to ensure sufficient fluidity of cement. This is because the conditions for producing an appropriate amount of melt phase necessary for producing clinker and the solid solution state of the rapid hardening component, that is, the conditions for maximizing the hydration activity do not necessarily coincide with each other. It was difficult to design so as to maximize the hydration activity.
In addition, these clinker are materials used in the manufacture of cement and are used to add to any cement afterwards to increase the hydration activity of the resulting cement upon use and to obtain any desired rapid hardening. is not.

Japanese Patent No. 4616113 Japanese Patent No. 3179702

The object of the present invention is to add good cement to the resulting cement composition to ensure good fluidity not only at room temperature but also at low temperatures, as well as excellent rapid hardening performance. It is to provide a rapid hardening additive for cement excellent in hydration activity and a method for producing the same.
In particular, the cement composition obtained by post-adding to any cement at the site, etc. is excellent in initial strength development at a low temperature such as 5 ° C. and is easy to pump, etc. It is to provide a rapid hardening additive for cement and a method for producing the same, which can be ensured.

The quick-hardening additive for cement according to claim 1 is an additive added later to the cement, wherein C12A7-based mineral phase is 70% by mass or more, C3A is 5.0% by mass or less, and Ti is 1 in terms of TiO _2. 0.02 mass% or less, Fe containing 1.5 mass% or less in terms of Fe ₂ O ₃ , the crystallite diameter of the C12A7 mineral phase measured by X-ray diffraction is 150 to 500 nm, and the C12A7 mineral phase It is a rapid hardening additive for cement characterized by having a lattice constant of 11.940 to 11.975 Å.

  The rapid hardening additive for cement according to claim 2, wherein the rapid hardening additive for cement according to claim 1, further containing 0.5 to 3.0% by mass of F. It is an additive.

The rapid hardening additive for cement according to claim 3 is the rapid hardening additive for cement according to claim 2, wherein the lattice constant of the C12A7 mineral phase measured by X-ray diffraction is expressed by the following formula:
Lattice constant of C12A7 mineral phase ≦ −0.93 × (mass% of F / mass% of C12A7 mineral phase) +11.98
Is a quick hardening additive for cement, characterized by satisfying

The rapid hardening additive for cement according to claim 4 is the rapid hardening additive for cement according to any one of claims 1 to 3, wherein the C12A7-based mineral phase is a mixed phase of C11A7CaX ₂ (X is halogen) and C12A7. It is.

  The method for producing a rapid hardening additive for cement according to claim 5, wherein the raw material is powdered, the powdered raw material is molded, the molded body is fired at 1250 to 1400 ° C., and the fired molded body is cooled at a cooling rate of 40. A method for producing a rapid hardening additive for cement according to any one of claims 1 to 4, wherein the rapid hardening additive for cement according to any one of claims 1 to 4 is obtained by cooling at a temperature of ° C / minute or less.

Further, in the method for manufacturing cement rapid hardening additive, it is not name for the control of the melt phase product in order to accelerate the solid state reaction.

The rapid-hardening additive for cement of the present invention is an additive for post-mixing with any cement, and is desired to improve the hydration activity of the resulting mortar and the like by post-mixing with any cement. It is possible to obtain excellent rapid hardening performance quickly and economically and to ensure excellent workability with a predetermined fluidity.
Therefore, it becomes possible to effectively apply at the work site or the like in the quick hardening application, and furthermore, by adding the quick hardening additive for cement of the present invention in an arbitrary amount depending on the desired initial strength, It becomes easy to design to obtain the desired rapid hardness, and excellent initial strength developability not only at room temperature but also at a low temperature of 5 ° C. or less.
Moreover, it is possible to have fluidity such as mortar using the rapid hardening additive for cement of the present invention, for example, pumping performance becomes good.

  The method for producing a rapid hardening additive for cement according to the present invention does not substantially require the production of a certain amount of melt phase, can easily produce the rapid hardening additive for cement according to the present invention, and has a special feature. Equipment and equipment are not required, and existing equipment can be used for economical production.

The present invention will be described with reference to the following embodiments, but is not limited thereto.
The rapid-hardening additive for cement according to the present invention is an additive added later to cement. The C12A7 mineral phase is 70% by mass or more, C3A is 5.0% by mass or less, and Ti is 1.0 in terms of TiO _2. C12A7 minerals containing 150 mass% or less, Fe containing 1.5 mass% or less in terms of Fe ₂ O ₃ , crystallite diameter of C12A7 mineral phase measured by X-ray diffraction, especially Rietveld method is 150 to 500 nm This is a rapid hardening additive for cement having a phase lattice constant of 11.940 to 11.975%.
Preferably, F is further contained in an amount of 0.5 to 3.0% by mass.
The rapid hardening additive for cement according to the present invention does not include Irwin.

  That is, it is an additive mainly composed of a C12A7 mineral phase, C3A is 5.0 mass% or less, substantially does not contain Ti or Fe as described below, and preferably F is 0.5%. It is added to cement that can be obtained in any market by containing ~ 3.0% by mass and making the crystallite diameter and lattice constant of the C12A7 mineral phase as the main component within a specific range. Improve the hydration activity of the resulting mortar, etc., regardless of the amount of melt phase produced, and ensure excellent fluidity at early temperatures, not only at room temperature but also at low temperatures. It will also be possible.

The rapid hardening additive for cement of the present invention contains 70 mass% or more, preferably 80 mass% or more of a C12A7 mineral phase that is a calcium aluminate phase.
The rapid-hardening additive for cement of the present invention is a rapid-hardening component that does not require control of melt phase generation for promoting a solid-phase reaction by introducing a molding process or the like for molding raw material powder during production. It becomes possible to maximize the hydration activity of the C12A7 mineral phase.
Therefore, the C12A7 mineral phase can be contained at a high content and the hydration activity can be improved. As a result, the effects of the present invention can be fully achieved.
When the content of the C12A7 mineral phase is less than 70% by mass, sufficient rapid hardening cannot be obtained, the initial strength is lowered, and the above-described effects of the present invention cannot be effectively obtained.
Here, C12A7 and C11A7 · CaX ₂ (X is a halogen such as F, Cl, Br, etc.) correspond to the C12A7 mineral phase, and a mixed phase thereof may be used.

  On the other hand, the rapid hardening additive for cement of the present invention should have a C3A content of at most 5.0% by mass and less, and is preferably substantially free of C3A content. When C3A exceeds 5.0% by mass, the content of the C12A7 mineral phase decreases, so that sufficient rapid hardening cannot be obtained, the initial strength is lowered, and the effect of the present invention cannot be obtained.

It is preferable that C2S and C2AS are not substantially contained in the rapid hardening additive for cement according to the present invention having the C12A7 mineral phase as a main component and having a C3A content of a certain level or less.
“Substantially not contained” means that these mineral phases do not hinder the case where they are produced by SiO ₂ which is an impurity contained in the raw material, and are not actively produced and contained. The total content of C2S and C2AS is preferably at most 10% by mass and less. This is because the content of the C12A7 mineral phase that is the calcium aluminate phase is not reduced from the above range.
In addition, the rapid hardening additive for cement of the present invention is prepared by firing at 1250 to 1400 ° C., preferably 1300 to 1360 ° C., as described below, so that almost no C ₃ S is generated. , Practically not included. Further, C4AF is hardly generated and hardly contained since Fe ₂ O ₃ in the rapid hardening additive for cement of the present invention is 1.5% by mass or less.

Moreover, the rapid hardening additive for cement of the present invention does not actively contain Ti and is not substantially contained.
The fact that it is not included means that Ti does not interfere with the case where it is generated by impurities contained in the raw material, and is not positively included.
For example, the Ti content is 1.0% by mass or less, preferably 0.5% by mass or less, in terms of TiO ₂ oxide.
That is, the rapid hardening additive for cement according to the present invention does not require the generation of a certain amount of melt phase, and therefore does not need to actively contain Ti related to the generation of the melt phase.
By making TiO ₂ substantially not contained and at most not more than the above-mentioned content, it is excellent in rapid hardening at low temperatures, for example, initial strength development at 5 ° C. or less (3 hours after construction, etc.).
When Ti is contained exceeding 1.0 mass% in terms of TiO ₂ , C3A is produced exceeding 5.0 mass%, and the effect of the present invention cannot be obtained.

Moreover, the rapid hardening additive for cement of the present invention does not actively contain Fe and is not substantially contained.
The fact that it is not included means that Fe does not interfere with the case where it is generated by impurities contained in the raw material, and is not positively included.
For example, the Fe content is 1.5% by mass or less, preferably 1.0% by mass or less, in terms of Fe ₂ O ₃ oxide.
That is, the rapid hardening additive for cement of the present invention does not require the production of a certain amount of melt phase, and therefore does not need to actively contain Fe that is related to the formation of the melt phase.
When Fe ₂ O ₃ is contained in excess of the above content, the lattice constant of the C12A7-based mineral phase increases, and rapid hardening at low temperatures, for example, initial strength development at 5 ° C. or lower (3 hours after construction, etc.) is poor. The smaller the better.

Preferably, the rapid hardening additive for cement of the present invention further contains 0.5 to 3.0 mass%, preferably 1.0 to 2.5 mass% of F.
By including F in such a range, the above-described effects of the present invention can be expressed more effectively.

The rapid hardening additive for cement of the present invention is desirable because it can be excellent in strength development for 3 hours even at a low temperature, for example, 5 ° C., by satisfying the following formula.
Y = −0.93 (F / Q) −Qa + 11.98 ≧ 0
In the above formula, F represents the fluorine content (mass%), Qa represents the lattice constant (Å) of the C12A7 mineral phase, and Q represents the content (mass%) of the C12A7 mineral phase.

The rapid hardening additive for cement according to the present invention includes calcium raw materials such as quick lime, slaked lime and limestone, aluminum raw materials such as aluminum hydroxide, alumina, bauxite and band shale, magnesium raw materials such as dolomite to be blended as necessary, Fluorine raw materials such as fluorite to be blended are mixed and pulverized, or pulverized and mixed, and this powder mixture is molded to obtain a molded body, which is heated by a heating means such as an electric furnace. It is fired and cooled to prepare a rapid hardening additive for cement.
In addition, what becomes the raw material (for example, Bengala etc.) of Ti and Fe contained in the rapid hardening additive for cement obtained is not mix | blended actively. Ti and Fe contained in the obtained rapid hardening additive for cement are sometimes included as a result of being contained as impurities in the blended raw material, and are not actively contained.

Specifically, the rapid hardening additive for cement according to the present invention is obtained by pulverizing and mixing a blended raw material, and molding a mixture obtained by molding the mixed powder, for example, 1250 to 1400 ° C, preferably 1300 to 1360 ° C. It is possible to produce by sufficiently baking, for example, 0.5 to 3 hours, and then cooling at a cooling rate of 40 ° C./min or less, preferably 5 to 40 ° C./min. In addition, a raw material is mix | blended so that it may become the content rate in the said invention.
The rapid hardening additive for cement of the present invention thus obtained does not require the generation of a certain amount of melt phase, that is, does not require control of the melt phase generation, so the C12A7 solid solution Ti, Fe, and the like are substantially not included so that the hydration activity of the material can be fully expressed, and at most, these contents are adjusted to be equal to or less than the above-mentioned contents, so that they are rapidly hardened, particularly at a low temperature of 5 ° C. The strength for 3 hours is excellent.

  In this way, the molded body obtained by molding the raw material mixed powder is fired and cooled at a cooling rate of 40 ° C./min or less, preferably 5 to 40 ° C./min, so that the C12A7 mineral phase measured by X-ray diffraction is measured. The rapid hardening additive for cement of the present invention having a crystallite diameter of 150 to 500 nm, preferably 150 to 300 nm, and a lattice constant of the C12A7 series mineral phase of 11.940 to 11.975% can be produced.

Because the crystallite size is different, the hydration activity, that is, the degree of rapid hardening, is different. Therefore, in order to secure the pot life and obtain rapid hardening, it is fired at the firing temperature or the like and further cooled. By setting the speed, a rapid hardening additive for cement having a crystallite diameter in the range of 150 to 500 nm can be obtained. Moreover, quick hardening will become more excellent by setting it as the suitable range of 150-300 nm.
When the crystallite size of the C12A7 mineral phase is within such a range, it is possible to maintain appropriate fluidity and obtain good initial strength development at low temperatures.
The crystallite diameter is a value measured by powder X-ray diffraction, and is a numerical value measured using an X-ray diffraction / Rietbelt method (apparatus: D4 Endeavor manufactured by Bruker, analysis software: Topas).
Tube voltage: 45 kV Tube current: 40 mA

Furthermore, the rapid hardening additive for cement of the present invention has a C12A7 mineral phase having a lattice constant of 11.940 to 11.975 mm, preferably 11.945 to 11.970 mm, as measured by X-ray diffraction. It is more desirable that the relationship satisfies the following formula.
Lattice constant of C12A7 mineral phase (（) ≦ −0.93 × (mass% of F / mass% of C12A7 mineral phase) +11.98

Since the degree of hydration activity, that is, the rapid hardening is different due to the difference in the lattice constant, in order to secure the pot life and obtain the rapid hardening, it is obtained by the manufacturing method such as the baking / cooling step. By using a rapid hardening additive for cement having a lattice constant in the above range, the effect of the present invention can be further improved.
When the lattice constant is within such a range, it is possible to secure predetermined fluidity and obtain rapid hardening at a low temperature.
The lattice constant is a value measured by powder X-ray diffraction, and is a value measured using an X-ray diffraction / Rietbelt method (apparatus: X'Pert MPD manufactured by Panaritical, analysis software: HighScorePlus). is there.
Tube voltage: 45 kV Tube current: 40 mA

The rapid hardening additive for cement according to the present invention is pulverized to obtain a rapid hardening additive powder for cement, and the powder is blended with an arbitrary cement, for example, ordinary Portland cement together with a sulfate or the like as a rapid hardening cement composition. It is possible to use.
The rapid hardening additive for cement according to the present invention is preferably used after being pulverized to have a specific surface area of 4500 cm ² / g or more. If this is less than 4500 cm ² / g, good rapid hardening may not be obtained. Because.
Further, if the Blaine specific surface area is too large, the flowability is adversely affected, and a pulverization time is required, resulting in a decrease in productivity and an increase in cost. Therefore, 5000 to 7000 cm ² / g is desirable.
Further, a grinding aid (diethylene glycol, triethanolamine, etc.) may be added when grinding.

  As the cement to which the rapid hardening additive for cement according to the present invention is blended, any commercially available cement can be applied. At least one selected from heat Portland cement, low heat Portland cement, sulfate-resistant Portland cement, fly ash cement, blast furnace cement, silica cement and the like can be used.

Examples of sulfates include alkaline metal sulfates such as sodium sulfate (sodium sulfate) and potassium sulfate, alkaline earth metal sulfates such as magnesium sulfate and gypsum (calcium sulfate), and aluminum sulfate. From the viewpoint of properties, it is preferable to use gypsum or a combination of gypsum and mirabilite.
Examples of the gypsum include anhydrous gypsum, hemihydrate gypsum, dihydrate gypsum, or a mixture thereof.
Moreover, slaked lime is mentioned as a material which can be mix | blended as needed.

  The mixing method of the cement quick hardening additive, cement, sulfate, water and the like of the present invention is not particularly limited, and after mixing in a predetermined ratio, mixing may be performed using a conventional mixing device.

  In addition, setting regulators (lignin sulfonic acid, oxycarboxylic acid, various organic acids such as saccharides, alkali metal salts or alkaline earth metal salts of organic acids) and water reducing agents (alkyl allyl sulfonic acid, naphthalene sulfonic acid) , Melamine sulfonic acid, polycarboxylic acid, AE water reducing agent, high performance water reducing agent, high performance AE water reducing agent), liquid or powder admixture, fine aggregate (river sand, sea sand, mountain Sand, crushed sand and mixtures thereof), coarse aggregate (river gravel, sea gravel, crushed stone and mixtures thereof) and the like can be blended.

  Thus, the rapid hardening additive for cement of the present invention can be added to any cement later, for example, to ensure workability by fluidity even in low-temperature work, and to exhibit good three-hour strength development. Therefore, the desired rapid hardening can be obtained on site, and the design of initial strength development can be operated very easily.

The present invention will be described based on the following examples, comparative examples and test examples.
(Examples 1-4, Comparative Examples 1-2)
1) Preparation of rapid hardening additive for cement To make the target chemical composition of rapid hardening additive for cement as shown in Table 1, CaCO ₃ , SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , MgO, TiO ₂ , CaF ₂ Each of the above reagents was mixed and pulverized to prepare a rapid hardening additive material for each cement. Here, Fe ₂ O ₃ and TiO ₂ are used as raw materials for calcium, such as quick lime, slaked lime, and limestone, when actually producing the rapid hardening additive for cement of the present invention using actual equipment, aluminum hydroxide, alumina, bauxite. When using raw materials such as aluminum raw materials such as shale and band shale, magnesium raw materials such as dolomite blended as necessary, and fluorine raw materials such as fluorite blended as necessary, Fe ₂ O ₃ and TiO ₂ are used as impurities. Since it may be included as a result (it is not what is contained actively), it is used assuming such a case.

  The above-mentioned cementitious hardened additive raw materials are pulverized and pressure-molded. Each molded body is fired at 1300 ° C. for 30 minutes in an electric furnace, and then cooled at each cooling rate shown in Table 2 for each cement. A quick hardening additive was obtained.

2) Measurement of content of TiO _2, Fe ₂ O ₃ , F component, etc. The obtained rapid hardening additives for cement were applied to JIS R 5204 using a fluorescent X-ray analyzer (manufactured by Panalical; Axios). analogously and analyzed to determine the content of such _{TiO 2, Fe 2 O 3,} F ingredients contained. The results are shown in Table 2.

3) Analysis of minerals for rapid hardening additives for cement (C12A7 series and C3A)
Using the X-ray diffraction / Rietbelt method (apparatus: X'Pert MPD, analysis software: HighScorePlus) made by each X-ray diffraction / Riet belt method, the content ratio of C12A7 series and C3A mineral and C12A7 The lattice constant of crystals of the mineral phase was measured. Tube voltage: 45 kV Tube current: 40 mA
The results are shown in Table 2. Here, the lattice constant of the crystal of the C12A7 series mineral phase was measured using the crystal structure of C11A7CaF2.

The crystallite size of the C12A7 mineral phase was measured by the X-ray diffraction / Rietvelt method (apparatus: D4 Endeavor manufactured by Bruker, analysis software: Topas) using the C11A7CaF2 crystal structure. Tube voltage: 45 kV Tube current: 40 mA
The results are shown in Table 2.

4) Preparation of cement composition Next, each of the above-mentioned cement hardeners was pulverized to a Blaine specific surface area of about 5200 ± 200 cm ² / g to obtain each cement hardener additive powder.
Haya strong cement (HC: manufactured by Sumitomo Osaka Cement Co., Ltd.) (excluding additive No. A), quick hardening additive powder for each cement, anhydrous gypsum (trade name; nonclave, manufactured by Sumitomo Osaka Cement Co., Ltd.) And each of the cement compositions was prepared by blending Na ₂ SO ₄ (bottle nitrate: reagent) at the blending ratio shown in Table 3 below.
The amount of early strong cement was adjusted so that the amount of crystals of the C12A7 mineral phase in the cement composition was equivalent (22% by mass).

5) Preparation of mortar Each cement composition described above, fine aggregate (sand (silica sand)), setting agent (reagent; citric acid, manufactured by Wako Pure Chemical Industries, Ltd.), water and admixture (Kao Corporation) And blended as shown in Table 4 below so that the water / cement composition substance ratio is 0.36 and the sand / cement composition substance ratio is 1.2. Each mortar was obtained.

6) Strength measurement and flow value measurement About each mortar obtained above, the strength for 3 hours (initial strength) at 5 ° C and the flow value at 5 ° C were measured according to JIS R 5201.
The results are also shown in Table 2 above.

(Examples 5-13, Comparative Examples 3-9)
1) Preparation of rapid hardening additive for cement The CaCO ₃ , SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ , MgO, TiO ₂ , and CaF ₂ so that the target chemical composition of the rapid hardening additive for cement is as shown in Table 5. Each of the above reagents was mixed and pulverized to prepare a rapid hardening additive material for each cement. Here, Fe ₂ O ₃ and TiO ₂ are used as raw materials for calcium, such as quick lime, slaked lime, and limestone, when actually producing the rapid hardening additive for cement of the present invention using actual equipment, aluminum hydroxide, alumina, bauxite. When using raw materials such as aluminum raw materials such as shale and band shale, magnesium raw materials such as dolomite blended as necessary, and fluorine raw materials such as fluorite blended as necessary, Fe ₂ O ₃ and TiO ₂ are obtained as impurities. In some cases, it is included (not positively included), and is used assuming such a case.

  The above-mentioned cement-hardening additive raw materials for each cement are pulverized and pressure-molded, each molded body is fired at 1300 ° C. for 30 minutes in an electric furnace, cooled at a cooling rate of 17 ° C./min, A hard additive was obtained.

2) Measurement of content of TiO _2, Fe ₂ O ₃ , F component, etc. The obtained rapid hardening additive for cement was subjected to JIS R 5204 using a fluorescent X-ray analyzer (manufactured by Panalical; Axios). The content ratios of TiO _2, Fe ₂ O ₃ , F component and the like contained were measured. The results are shown in Table 6.

3) Analysis of minerals for rapid hardening additives for cement (C12A7 series and C3A)
Using the X-ray diffraction / Rietbelt method (apparatus: X'Pert MPD, analysis software: HighScorePlus) made by each X-ray diffraction / Riet belt method, the content ratio of C12A7 series and C3A mineral and C12A7 The lattice constant of crystals of the mineral phase was measured. Tube voltage: 45 kV Tube current: 40 mA
The results are shown in Table 6. Here, the lattice constant of the crystal of the C12A7 series mineral phase was measured using the crystal structure of C11A7CaF2.

The crystallite size of the C12A7 mineral phase was measured by the X-ray diffraction / Rietvelt method (apparatus: D4 Endeavor manufactured by Bruker, analysis software: Topas) using the C11A7CaF2 crystal structure. Tube voltage: 45 kV Tube current: 40 mA
The results are shown in Table 6.

4) Preparation of cement composition Next, each of the above-mentioned cement hardeners was pulverized to a Blaine specific surface area of about 5200 ± 200 cm ² / g to obtain each cement hardener additive powder.
Haya strong cement (HC: manufactured by Sumitomo Osaka Cement Co., Ltd.), quick hardening additive powder for each cement, anhydrous gypsum (trade name; non-clave, manufactured by Sumitomo Osaka Cement Co., Ltd.) and Na ₂ SO ₄ (bottle nitrate: reagent) ) Were blended at the blending ratios shown in Table 7 below to prepare each cement composition.
The amount of early strong cement was adjusted so that the amount of crystals of the C12A7 mineral phase in the cement composition was equivalent (22% by mass).

5) Preparation of mortar Each cement composition described above, fine aggregate (sand (silica sand)), setting agent (reagent; citric acid, manufactured by Wako Pure Chemical Industries, Ltd.), water and admixture (Kao Corporation) And blended as shown in Table 8 below so that the water / cement composition substance ratio is 0.36 and the sand / cement composition substance ratio is 1.2. Each mortar was obtained.

6) Strength measurement and flow value measurement About each mortar obtained above, the strength for 3 hours (initial strength) at 5 ° C and the flow value at 5 ° C were measured according to JIS R 5201.
The results are also shown in Table 6 above.

From Table 6, Examples 5 to 13 are superior to Comparative Examples 3 to 9 in that post-addition of a cement hardening additive to cement is excellent in the strength of the obtained mortar at 5 ° C for 3 hours, Preferably, it can be set to 7.0 N / mm ² or more, and the flow value is 180 mm or more, has high rapid hardening even at low temperatures, has excellent initial strength, and has sufficient fluidity. Recognize.

  By adding the rapid hardening additive for cement of the present invention to any cement, it becomes easy to design the desired rapid hardening not only at room temperature but also at low temperatures, and construction work and civil engineering work in tunnels and underground spaces , Waterproofing work, spraying work on wall surfaces, repair work on roads with urgency, etc., and as soil improvement material, ensuring the specified handling time and developing strength immediately after the pot life has elapsed Can be usefully applied in the field to the work site where is required.

Claims (5)

A additives post-added to the cement, C12A7 based mineral phase 70 mass% or more, C3A 5.0 mass% or less, 1.0 wt% of Ti in terms of TiO ₂ or less, the Fe _Fe 2 _{O 3} in terms of The crystallite size of the C12A7 mineral phase measured by X-ray diffraction is 150 to 500 nm and the lattice constant of the C12A7 mineral phase is 11.940 to 11.975９. A quick hardening additive for cement, characterized by   The rapid hardening additive for cement according to claim 1, further comprising 0.5 to 3.0% by mass of F. In the rapid hardening additive for cement according to claim 2, the lattice constant of the C12A7 mineral phase measured by X-ray diffraction is expressed by the following formula:
Lattice constant of C12A7 mineral phase ≦ −0.93 × (mass% of F / mass% of C12A7 mineral phase) +11.98
Quick hardening additive for cement, characterized by satisfying The rapid hardening additive for cement according to any one of claims 1 to 3, wherein the C12A7 mineral phase is a mixed phase of C11A7CaX ₂ (X is halogen) and C12A7. Wood.   Either the raw material is powdered, the powdered raw material is molded, the molded body is fired at 1250 to 1400 ° C, and the fired molded body is cooled at a cooling rate of 40 ° C / min or less. A method for producing a cement hardening additive, comprising obtaining the cement hardening additive described in the above section.